Arduino_40hz_light_program.cpp

const int knobPin = 3;
const int onButtonPin = 2;
const int relayPin = 4;
const int potPin = 2; //analog

int onButtonState = 0;
int potVal;
bool onState;

int hertz;
int uptime;
int downtime;

void setup() {
  Serial.begin(9600);
  pinMode(onButtonPin, INPUT);
  pinMode(knobPin, INPUT);
  pinMode(relayPin, OUTPUT);
  onState = false;
}

void loop() {
  onButtonState = digitalRead(onButtonPin);
  potVal = analogRead(potPin);
  
  if (onState) {
    programLoop(); //program
  }
  
  //changes state of program.
  if (onButtonState == HIGH) {
    if (onState) {
      onState = false;
      
      //deinitialize all
      toggleRelay(false);
      
    } else {
      onState = true;
    }
    delay(1000);
  }
}

void programLoop() {
  uptime = map(potVal, 0, 1023, 750, 2250); //(potentiometer input maps to:, min analog, max analog, 30% of 25000, 90% of 2500);
  downtime = 25000 - uptime;
  occilate();
}
void toggleRelay(bool state) {
  if (state) {
    digitalWrite(relayPin, HIGH);
  } else {
    digitalWrite(relayPin, LOW);
  }
}

void occilate() {
  toggleRelay(true);
  microsDelay(uptime);
  toggleRelay(false);
  microsDelay(downtime);
}

void microsDelay(int micros1) {
  while (micros() >= (micros() + micros1)) {}
}
int changeBrightness(float percent) {
  int Brightness =((int)(percent * 100));
  Brightness = map(Brightness, 0, 1023, 0, 100);
  analogWrite(transPin, Brightness);
  return Brightness;
}